The new Nook Tablet during a demonstration at the Union Square Barnes & Noble in November. Photo: REUTERS

Ex-SAC exec Mathew Martoma leaves court with his wife Rosemary yesterday after pleading not guilty to charges tied to what feds call the most lucrative insider-trading scheme ever. (Brigitte Stelzer)

Hedge-fund titan Steve Cohen must be breathing a little easier.

Six weeks after Mathew Martoma, a former portfolio manager at Cohen’s SAC Capital Advisors, was arrested by FBI agents and charged with insider trading, the mid-level exec is still set against cooperating with prosecutors.

Martoma’s lawyer said as much yesterday when asked by reporters if the 38-year-old trader was seeking a plea deal.

“No,” he said.

The FBI has been trying to flip Martoma since he was arrested outside his Boca Raton, Fla., estate on Nov. 20.

Flanked yesterday by his pediatrician wife, Rosemary, Martoma pleaded not guilty to charges he profited in the most lucrative insider-trading case ever.

Despite the cold temperatures, Martoma was dressed simply in grey slacks and a brown tweed jacket.